In microelectronics, semiconductor wafers, thin films and foils are often cut with diamond saws. A problem with such cutting is that the saw removes material at a kerf, thereby diminishing the overall amount of material. Where the overall amount of material is useful in performance of an electronic function, or very valuable due to chemical composition or fabrication difficulty, the removed material constitutes significant loss. Another problem is that a saw generates particles that must be captured or removed in order to prevent contamination of active surfaces.
An alternative to sawing is cutting by means of a die or blade. In the prior art, a sharp die has been used to engage a thin substrate such as a foil, for example carrying a circuit pattern, by pressing the foil into an underlying support to cut the desired circuit pattern from the foil. One of the problems with dies is that to achieve regularity of the cut, the die must be pressed through the foil into a substrate since force for separation is essentially vertical, thereby bending the foil where such pressing occurs. Bending causes slippage of crystal structures, affecting electronic properties and is therefore deleterious. Sometimes dies have been used to cut foil without pressing into a substrate but such dies must be kept very sharp over a uniform area to be effective.
Blade shearing has been used for separating flat or nearly flat thin substrates. Blade shearing is advantageous in that there is minimal material loss due to kerf marks and tearing. However, dicing yield and throughput can be adversely affected by human error when the thin substrate is manually visually aligned to the blade before shearing.
Also, thin foils are not always flat and can have a spring-like resiliency that causes uncut and cut sections to roll or bow independently thus compromising foil dicing accuracy.
An objective of the invention is to cut thin substrates without deformation and without loss of material.
Another objective of the invention is to make precise, reproducible cuts in thin substrates.